Substituted 5-nitroimidazoles

ABSTRACT

THIS INVENTION RELATES TO CHEMICAL COMPOUNDS OF THE CLASS 1 -SUBSTITUTED-5-NITRO-SUBSTITUTED IMIDAZOLES AND METHODS FOR THE PREPARATION THEREOF. THESE COMPOUNDS ARE USEFUL FOR THEIR ANTI-MICROBIAL ACTIVITY.

United States Patent U.S. Cl. 260-309 3 Claims ABSTRACT OF THEDISCLOSURE This invention relates to chemical compounds of the class 1substituted nitro-2-substituted imidazoles and methods for thepreparation thereof. These compounds are useful for their anti-microbialactivity.

This application is a continuation-in-part of application Serial No.766,984, filed Oct. 11, 1968, now abandoned.

SUMMARY OF THE INVENTION The present invention relates to new chemicalcompounds of the formulae:

and

owl gi EJYEZI E E Hz-CH: B

| R. loweralkyl 0 wherein Q is a member selected from the groupconsisting of hm h wherein R is loweralkyl or hydroxyloweralkyl; R isloweralkyl; R and R are hydrogen or loweralkyl; R is lower alkyl, amino,monoloweralkylamino, or diloweralkylamino with the proviso that informulae B and C R cannot be loweralkyl; R is loweralkyl, hydroxy,amino, monoloweralkylamino, or diloweralkylamino, R is lower alkyl; R,is hydroxy or amino; X is NH, oxygen, or sulfur and Y is NH or oxygen.The term lower alkyl is intended to include those containing from 1 to 4carbon atoms. When an amino, monoloweralkylamino, or hydroxy group isattached to the triazole ring the compound may exist, at least in part,in the tautomeric imino or keto forms.

The invention also relates to methods for the preparation of thesecompounds, one of which involves the reaction of animidazolecarboximidate or an acid chloride of the formulae:

N -N I I l l OzN -ORi O2N C C] N N l l Ra Ra wherein R and R areloweralkyl or of with a semicarbazide, thiosemicarbazide, acylhydrazideor aminoguanidine of the formula:

wherein R R and X are as defined above, to obtain animidazolecarboximidoyl or imidazolecarbonyl compound or a nitrogenousderivative of an alkyl imidazolecarboxylate of the formulae:

| R2 i O R zCHz-O B 0R1 R: X

loweralkyl C wherein R, R R R X and Y are as defined above, andcyclizing said compound by subjecting the same to heat treatment, acidtreatment or treatment with a condensing agent to yield a cyclizedproduct of the formula selected from the group consisting of O N LZHE it1'1,

I R R R m wherein Z is sulfur or oxygen and R, R R R R are as definedabove and R and R are hydrogen or lower alkyl.

PREFERRED EMBODIMENT zide by reaction with an acylhydrazine,aminoguanidine, semicarbazide or thiosemicarbazide, respectively. Thisreaction is preferably carried out in the presence of a solvent inert tothe reaction such as a loweralkanol, glacial acetic acid or aqueousalcoholic mixtures and at a temperature between about 20 C. and 100 C.although somewhat higher or lower temperatures may be employed. In thecase of reaction of the carboxirnidate with thiosemicarbazide orsubstituted thiosemicarbazides, it is found that acid catalysis isnecessary, the reaction preferably being carried out in glacial aceticacid or in an alcoholic solvent to which 1 to 50% by volume of aceticacid or catalytic amounts of mineral acids are added. When mineral acidsare used, it is frequently found that mixtures of imidazolecarboximidoylthiosemicarbazides with alkyl l-substituted 5nitro-2-imidazolecarboxylate thiosemicarbazones are formed. The lattercompounds are obtained as important components of the mixtures, and maybe isolated, when 1 or more equivalents of mineral acid, rather than acatalytic amount, is used.

Cyclization of the thus prepared imidazolecarboximidoyl acylhydrazines,amidinohydrazines, or semicarbazides then yields thetriazol-3-yl-5-nitroimidazoles. Cyclization of the 4imidazolecarboximidoylthiosemicarbazides or the mudazolecarboxylatethiosemicarbazones gives Z-(Z-amino-l,3,4-thiadiazol-5-yl)-5-nitroirnidazoles. These reactions, in the case ofthe triazol-3-yl-5-nitroirnidazoles, are general ly most favorablycarried out by heating, preferably refluxing, in the presence of anorganic solvent such as nitrobenzene, dimethylformamide or glacialacetic acid. In the case of the thiadiazol-S-yl-S-nitroimidazoles acidcatalysis is generally most advantageously employed. Acidic reagentssuch as aqueous, methanolic, or ethanolic sulfuric or hydrochloric acidsare preferred, however, other acids such as phosphoric, nitric,hydrobromic trifluoroacetic and aliphatic or aromatic sulfonic acids mayalso be used. p-Toluene sulfonic acid and methylsulfonic acids aretypical of these latter acid groups. In practice it is also found thatthe acid catalysts may be conducted in systems free of solvent or in thepresence of solvents other than water or lower alcohols. Furthermore, ithas been found that these reactions are generally most advantageouslycarried out at temperatures between 0 C. and 150 C. and preferably 50 C.and 100 C.

Graphically, such reactions may be illustrated as follows:

Continued on Column 5.

(VIP) (VIH) VII (VIIA) Fen, (VIIB) a a R7=HH2 IIII IV or V acid VIII

(VIIIB) n=c1-r (VIIID) R=CH2CH=0H (vine) wherein R is lower alkyl and R,R R R R R R R R R X and Y are as hereinbefore described.

Also, in accordance with the invention al-loweralkylsubstituted-5-nitro-2-imidazolecarboxylic acid is treatedwith oxalyl chloride to give the l-loweralkyl-S-nitro-Z-imidazolecarboxylic acid chloride which is converted to thecorresponding Z-imidazolecarbonyl semicarbazide or thiosemicarbazide byreaction with semicarbazide or thiosemicarbazide in an organic solvent.When the thus prepared semicarbazide or thiosemicarbazide has RFH (seebelow), it can then be cyclized to the oxadiazolyl or thiadiazolylimidazoles by treatment thereof, in the case of the thiosemicarbazide,with a strong mineral acid at an elevated temperature preferably betweenabout 50 C. and C. and, in the case of the semicarbazide, with acondensing agent such as phosphorus oxychloride or thionylchloride. Theoxadiazolyl or thiadiazolyl imidazole is then readily recovered from thereaction mixture by treatment of the mixture with water, followed byfiltration.

The reactions are illustrated graphically below:

cn wii,

wherein Z is oxygen or sulfur and R R and R are as hereinbeforedescribed.

The process of the present invention is highly effective for thepreparation of compounds useful for the control of bacterial, parasiticand protozoal infections in poultry and animals.

The novel compounds of the invention find utility as antimicrobialagents effective against T richomonas vaginalis and Salmonellagallinarwm infections in poultry and animals and also show a substantialamount of seedicidal activity in the plant science area. For thetreatment of animals and poultry generally about 0.025% to 0.1% byweight of the active compound will be thoroughly admixed with the foodand administered as such to said animals or poultry. If desired,however, the compounds may be prepared as liquids for use in drinkingwater or as an oral drench, in which case the active compound isdissolved or suspended in a non-toxic pharmaceutically acceptablecarrier and administered in an amount suflicient to produce generallyabout 100 to 1,000 mg./kg., and preferably 100 to 500 mg./kg. of bodyweight of active material to the animal under treatment.

DETAILED DESCRIPTION The following examples describe in detail thepreparation of representative compounds of this invention and their usein treating fowl typhoid, enteritis and colibacillosis.

7 EXAMPLE 1 Preparation of2-(1-methyl-5-nitro-2-irnidazolecarboximidoyl)-l-acetylhydrazine (IIIA)In 200 ml. of methanol, 12 g. (0.06 mole) of ethyl1-methyl-5-nitro-2-imidazolecarboximidate and 4.9 g. (0.066 mole) ofacetyl hydrazine are refluxed for 30 hours. The yellow compound iscollected, washed with cold methanol and dried to give 12.97 g. of thetitle compound, melting point 294 C.

Similarly, 2-propionylhydrazine is reacted withethyl-lmethyl--nitro-2-imidazolecarboximidate to afiord 2-(1-methyl-S-nitro 2 imidazolecarboximidoyl)-l-propionylhydrazine (1110).

In the above manner, 2-(l-(2hydroxyethyl)-5-nitro-2-imidazolecarboximidoyl)-l-acety1hydrazine (HIP), is prepared by reactingacetyl hydrazine with the cyclic iminoester of the formula:

The cyclic iminoester is prepared by reacting Zcyano-I-(2-hydroxyethyl)-5-nitroimidazole in inert solvent with alkali metalalkoxide.

EXAMPLE 2 Preparation of 2-(5-methyl-4H-1,2,4-triazol-3-yl)-1-methyl-S-nitroimidazole (VIA) In 100 ml. of glacial acetic acid 6.2 g.(0.0274 mole) of Z-(I-methyl-S-nitro 2imidazolecarboximidoyl)-lacetylhydrazine is refluxed for 4V2 hours. Themixture is cooled, diluted with water to give 5.33 g. of the abovecompound, melting point 329-333 (dec.).

In the same manner2-(5-etl1yl-4H-l,2,4-triazol-3-yl)-lmethyl-S-nitroimidazole (VII) isprepared from 2-(1- methyl-S-nitro 2imidazolecarboximidoyl)-1-propionylhydrazine.

Using the above procedure2-(5-methyl-4H-1,2,4-triazol-3-yl)-l-(2-hydroxyethyl) 5 nitroimidazole(VII) is prepared from 2-[1-(2-hydroxyethyl)-5-nitro-2-imidazolecarboximidoyl)-1-acetylhydrazine.

EXAMPLE 3 Preparation of2-(1-methyl-5-nitro-2-imidazolecarboximidoyl)-1-amidino hydrazinehydrochloride (IIIB) In ml. of ethanol, 8.2 g. (0.06 mole) ofaminoguanidine bicarbonate is treated with saturated ethanolic hydrogenchloride until carbon dioxide is no longer evolved. The mixture isevaporated to dryness, 90 ml. of dry dimethylformamide and 11.9 g. (0.06mole) of ethyl- 1-rnethy1-5-nitro-2-imidazolecarboximidate are added togive a yellow slurry which is heated at 65-70 C. for 1 /2 hours withstirring. The mixture is cooled, 160 ml. of ether added, and the abovecompound collected, melting point 273274 C. (dec.); the yield is 12.6 g.(80%).

Similarly, 2-(1-methyl-5-nitro-2-imidazolecarboximido yl)-1-amidinolmethylhydrazine hydrochloride (IIIC) and 2-(1-methyl-5-nitro 2irnidazolecarboximidoyl)-1- methylamidinohydrazine hydrochloride (HID)are prepared by reacting ethyl-l-methyl-5-nitro-2-imidazolecarboximidatewith l-amino-l-methylguanidine hydrochloride andl-amino-S-methylguanidine hydrochloride, respectively. In the likemanner, 2-[1-(2-hydroxyethyl)-5-nitro-2-imidazolecarboximidoyl]-l-amidinohydrazine hydrochloride (IIIE) isprepared by reacting aminoguanidine hydrochloride with the cyclicimiri'o ester described in Example l.

EXAMPLE 4 Preparation of2-(5-amino-4H-1,2,4-triazol-3-yl)-lmethyl-S-nitroimidazole (VIB) In 110ml. of nitrobenzene, 7.6 g. (0.029 mole) of 2-(1-methyl-5-nitro-Z-imidazolecarboximidoyl) l-amidinohydrazinehydrochloride is stirred at reflux temperature for 2% hours, cooled, andthe solid collected. This solid is Washed with ethyl alcohol, ether, andair-dried to give 6 g. of the title compound, melting point 278-280(dec.). The product is purified by removing soluble impurities in aSoxhlet extractor with 95% ethanol. The insoluble products melt at297-299 (dec.).

In the same manner, a mixture of2-(4H-5-methylamino-l,2,4-triazol-3-yl)-1-methyl-S-nitroimidazole (VIC)and 2 (5-amino-4-methyl-l,2,4-triazol-3-yl)-l-methyl-5- nitroimidazole(VID) are prepared from 2-(l-methyl-5- nitro-2-imidazolecarboximidoyl) 1methylamidinohydrazine hydrochloride, and2-(S-amino-l-methyl-l,2,4-triazol-3-yl)-1-methyl-5-nitroimidazole (VIIA)is prepared from 2-(1-methyl 5 nitro-Z-imidazolecarboximidoyl)-1-amidino-l-methylhydrazine hydrochloride.

Similarly, 2-(5-amino-4I-I-1,2,4-triazol 3yl)-l-(2-hydroxyethyl)si-nitroimidazole (VIE) is prepared from2-[1-(2-hydroxyethyl)-5-nitro 2imidazolecarboximidoyl]-1-amidinohydrazine hydrochloride.

EXAMPLE 5 Preparation of1-(1-methyl-5-nitro-2-imidazolecarboximidoyl)-semicarbazide (IIIF) Theabove compound is prepared by stirring a powdered mixture of 19.8 g.(0.1 mole) of ethyl 1-methyl-5-nitro 2-imidazolecarboximidate and 11.2g. (0.1 mole) of semicarbazide hydrochloride in 200 ml. of 50% aqueousethanol. The yellow product is collected after minutes and Washed withwater, methanol, and ether, respectively, melting point above 300 C.;the yield is 10 g. (44%).

The addition of 0.122 mole of sodium acetate to the mixture improved theyield to 86%.

In a similar manner, 2-ethylsemicarbazide and 4-methylsemicarbazide arereacted with ethyl 1-methyl-5-nitro-2- imidazolecarboximidate to givel-(l-methyl-S-nitro-Z- imidazolecarboximidoyl)-2-ethylsemicarbazide(IIIG) and 1(1-methyl-5-nitro-2-imidazolecarboximidoyl)-4-methylsemicarbazide(IIIH), respectively.

Similarly, 1-[1-(2-hydroxyethyl)-5-nitro 2imidazolecarboxirnidoyl]semicarbazide (III I) is prepared by reactingsemicarbazide hydrochloride with the previously mentioned cycliciminoester of Example 1.

EXAMPLE 6 Preparation of1-(l-methyl-5-nitro-2-imidazolecarboximidoyl)-3-thiosemicarbazide (111])A mixture of 1.0 g. of ethyl l-methyl-S-nitro-Z-imidazolecarboximidateand 0.46 g. of thiosemicarbazide in 20 ml. of glacial acetic acid isheated at reflux for 45 minutes. Water is added and the yellow solid isfiltered, washed with water and dried affording the amidine, meltingpoint 210-212 C., dec.

When the above procedure is carried out using 4-methyl-3-thiosemicarbazide and 4,4-dimethyl-3-thiosemicarbazide, 4methyl-1-(l-methyl-5-nitro-2-imidazolecarboximidoyl)-3-thiosemicarbazide=(III'K) and 4,4dimethyl-l-(l methyl-S-nitro-2-imidazoleca.rboximidoyl)-3-thiosemicarbazide (IIIL) are obtained.

In a similar manner, 1-[l-(2-hydroxyethyl)-5-nitro-2-imidazolecarboximidoyl]-3-thiosemicarbazide (IIIM) is obtained bytreating 1-(2-hydroxyethyl)-5-uitro-2-irnidazolecarboximidic acid,delta-lactone, with thiosemicarbazide.

According to the above procedure, ethyl l-ethyl-S-nitro-2-imidazolecarboxirnidate and thiosemicarbazide are allowed toreact to give 1-(l-ethyl-5-nitro-2-imidazole= carboximidoyl-3-thiosemicarbazide (IIIN) 9 EXAMPLE 7 Preparation of l-(l-methyl--nitro-2-imidazolecarbonyl)- 3-thiosemicarbazide (XIA) To 5 ml.of oxalyl chloride, stirred in ice bath, is added 1.0 g. ofl-methyl-S-nitro-2-imidazolecarboxylic acid, in portions. The resultingsuspension is stirred at room temperature overnight. Benzene is added,the mixture is filtered and the filtrate is evaporated to dryness. Theresidue, 1-methyl-5-nitro-2-imidazolecarboxylic acid chloride, issufliciently pure to use in subsequent reactions.

To 1-methyl-S-nitro-Z-imidazolecarboxylic acid chloride (1.1 g.) in 25ml. of dry tetrahydrofuran is added 0.55 g. powdered thiosemicarbazideand the mixture is stirred at room temperature for 24 hours. Thereaction mixture is evaporated to dryness and water is added. Thesolution is made basic with sodium hydroxide and the solid is filtered,washed with water and dried afiording 1 (1-methyl 5nitro-2-imidazolecarbonyl)-3-thiosemicarbazide.

When the above procedure is followed using4-isopropyl-3-thiosemicarbazide and4-ethy1-2-methyl-3-thiosemicarbazide, 1-1-methyl-5-nitro-2-imidazolecarbonyl) 4-isopropyl-3-thiosemicarbazide(XIB) and 4-ethyl-2- methyl 1 (1 methyl-5-nitro-2-imidazolecarbonyl)-3-thiosemicarbazide (XIC), respectively, are obtained.

In a similar manner, 2-(1-methyl-5-nitro-2-imidazolecarbonyl) 1amidinohydrazine (XID), l-(l-methyl-S-nitro-2-imidazolecarbonyl)semicarbazide (XIE), and 1- (l-methyl 5nitro-2-imidazolecarbonyl)-4-methylsemicarbazide (XIF), are obtainedfrom the reaction of 1- methyl-S-nitro-2-imidazolecarboxylic acidchloride with aminoguanidine bicarbonate, semicarbazide and4-methylsemicarbazide, respectively.

EXAMPLE 8 Preparation of 1-[1-(Z-hydroxyethyl)-5-nitro-2-imidazolecarbonyl] -3 -thiosemicarbazide (XIG) A mixture of1-(2-hydr0xyethyl)-5-nitroimidazole-2- carboxylic acid delta-lactone(1.83 g.) and thiosemicarbazide (0.91 g.) in 50 ml. of tetrahydrofuranis heated at reflux for three hours. The solvent is evaporated and theresidue is slurried with water and the solid is filtered, Washed withwater and dried giving 1-[l-(2-hydroxyethyl) -5-nitro-2-imidazolecarbonyl] -3 -thiosemicarbazide.

EXAMPLE 9 Preparation of 2-(2-amino-1,3,4-thiadiazol-5-yl)-1-methyl-S-nitroimidazole (VIIIA or XIIC) To 0.05 g. of1-(1-methyl-5-nitro-2-imidazolecarbonyl)- 3-thiosemicarbazide is added0.5 ml. of cone. sulfuric acid and the mixture is heated on a steam bathfor 30 minutes. Ice is added to the reaction mixture and the solid isfiltered. The filtrate is made basic with sodium hydroxide and cooled inan ice bath. The solid is filtered, washed with water and driedatfording 17 mg. (37%) of 2-(2- amino- 1,3 ,4-thiadiaZol-5-yl)l-methyl-S -nitroimid azole.

EXAMPLE 10 Preparation of 2-(Z-amino-1,3,4-thiadiazol-5-yl)-1-methyl-S-nitroimidazole (VIIIA) l-(l-methyl 5 nitro 2imidazolecarboxirnidoyl)-3- thiosemicarbazide (0.3 g.) is heated with 7ml. of 6 N hydrochloric acid for minutes. The resulting solution iscooled and diluted with water. The solid is filtered, washed with waterand dried atfording 2-(2-amino-1,3,4-thiadiazol-5-yl)-1-methyl-5-nitroimidazole, melting point 266-8.

In a similar manner, 4,4-dimethy1-1-(l-methyl-S-nitro-Z-imidazolecarboximidoyl)-3-thiosemicarbazide, 4-methyll-(l-rnethyl 5nitrO-Z-imidazolecarboximidoyl)-3-thiosemicarbazide and1-(1-[2-hydroxyethyl]-5-nitro-2-imidazolecarboximidoyl)-3-thiosemicarbazideyield respectively, 2-(2-dimethylamino 1,3,4thiadiazol-S-yl)-l-methyl-5- nitroimidazole (VIIIB), 2-(2-methylamino1,3,4 thiadiazol-5-yl)-l-methyl-5-nitroimidazole (VIIIC) and 2-(2-amino-1,3,4-thiadiazol-5-yl) 1 (2 hydroxyethyl)-5- nitroimidazole(VIII'D). According to the above procedure, 2 (2amino-1,3,4-thiadiazol-5-yl)-1-ethy1-5-nitr0- imidazole (VIIIE) isobtained from l-(l-ethyl-S-nitro-Z- imidazolecarboximidoyl)-3-thiosernicarbazide.

EXAMPLE 1 1 Preparation of 2-(Z-amino-l,3,4-oxadiazol-5-yl)-1-methyl-S-nitroimidazole (XIIA) l-(l-methyl-S-nitro 2imidazolecarbonyl)semicarbazide (5 g.) is heated under reflux in 50 ml.of phosphorus oxychloride for 1 hour. The reaction mixture is addedslowly to water maintained at 15 C. by occasional additions of ice. Theaqueous mixture is brought to pH 7 with potassium carbonate and thesolid 2-(2-amino-1,3,4- oxadiazol-S-yl) 1 methyl-S-nitroimidazolefiltered off, washed with water, and dried.

In similar fashion, 2-(2-methylamino-1,3,4-oxadiazol-5-yl)-1-methyl-5-nitroimidazole (XIIB) is prepared from 1-(1-methyl 5nitro 2 imidazolecarbonyl)-4-methylsemicarbazide.

EXAMPLE 12 Preparation of 1-methyl-5-nitro-2-[5-oxo-(A -l,2,4-triazolin-3-yl) ]-imidazole (VIF) WNUJLNLO In 50 ml. ofdimethylformamide, 7.8 g. of l-(l-methyl- 5 nitro 2imidazolecarboximidoyl)semicarbazide is stirred at 140-150 C. until theyellow solid darkens, dissolves to give a dark-brown solution, andbegins to deposit grey crystals. The mixture is cooled, diluted with ml.of ethyl alcohol, poured onto ice, and the solid collected. This solidis washed with hot dirnethylformamide to give the light-brown titlecompound, melting point 320.

Similarly, I methyl-5-nitro-2-[1-ethyl-5-oxo(A -1,2,4-triazolin-3-yl)]imidazole (VIIB) and 1-methyl-5nitro-2 [4-methyl 5 0x0(A -1,2,4-triazolin-3-yl)]imidazole (VIG) are prepared from 1-(1-methyl-5-nitro-2-imidazolecarboximidoyl) 2 ethyl-semicarbazide and1-(1- methyl 5 nitro-Z-imidazolecarboximidoyl)-4-methylsemicarbazide,respectively.

Similarly, 1-(2-hydroxyethyl) 5 nitro-2-[5-oxo-(A1,2,4-triazolin-3-yl)Jimidazole (VIH) is prepared from1-[1-(2-hydroxyethyl) 5 nitro 2 imidazolecarboximidoyl] semic arbazide.

IT-N N NH OQN JA (EH2 C Hz 0 H l l (VIH) EXAMPLE 13 Preparation of1-(1-methyl-5-nitro-2-imidazolecarboximidoyl) -3-thiosemicarbazide (IIIJTo a stirred solution of ethyl l-methyl-S-nitro-Z-imidazolecarboximidate(0.198 g., 0.001 mole) in 10 ml. of absolute ethanol is addedthiosemicarbazide (0.091 g.,

0.001 mole) and 1 ml. of glacial acetic acid. The mixture is heated atreflux for 1%. hours and is cooled in an ice bath. The orange-red solidis filtered, washed and dried affording 0.173 g. of the title compound,melting point 210-214, dec.

When an equimolar amount of methyl l-methyl-S-nitro-2-imidazolecarboximidate is substituted for the ethyl carboximidate inthis procedure and the reaction mixture stirred at room temperature for3 hours, the compound (IHJ) is also obtained in good yield.

EXAMPLE 14 Preparation of 1-(l-methyl-S-nitro-imidazolecar boximidoyl)-3-thiosemicarbazide (IIIJ To a stirred mixture of ethyll-methyl-S-nitro-2-imidazolecarboximidate (0.198 g., 0.001 mole) andthiosemicarbazide (0.091 g., 0.001 mole) in 5 ml. of methanol is added 1drop of conc. H 50 and the mixture is stirred at room temperature for 50minutes. The solid is filtered and washed with methanol, yielding 0.149g. of the title compound, melting point ZOO-201 C. dec.

EXAMPLE 15 Preparation of ethyl 1-methyl-5-nitro-2-imidazolecarboxylatethiosemicarbazone (IVA) and l-(l-rnethyl-S-nitro-Z-imidazolecarboximidoyl) -3-thiosemicarbazide T a mixture ofethyl 1-methyl-5-nitro-2-imidazolecarboximidate (1.98 g., 0.01 mole) andthiosemicarbazide (0.91 g., 0.01 mole) in 50 ml. of absolute ethanol isadded 5.37 N ethanolic HCl (1.86 ml., 0.01 mole). The mixture is stirredat room temperature for 3 /2 hours. The yellow solid is filtered, washedwith ethanol and dried, giving 1.27 g. of a mixture ofl-(l-methyl-S-nitro-Z- imidazolecarboximidoyl)-3-thiosemicarbazide andethyl 1- methyl-S-nitro-2-imidazolecarboxylate thiosemicarbazone. Themixture is recrystallized from dry dimethylsulfoxide, alfording 0.315 g.of ethyl 1-methyl-5-nitro-2-imidazolecarboxylate thiosemicarbazone,melting point 202-204 dec. Both infrared and nuclear magnetic resonancespectra show the presence of an ethoxyl group in this product.

When the above procedure is carried out using 4-methyl-3-thiosemicarbazide and 4,4-dimethyl-3-thiosemicarbazide, the4-methyl-3-thiosemicarbazone of ethyl 1-methyl-S-nitro-Z-imidazolecarboxylate and the4,4-dimethyl-S-thiosemicarbazone of ethyl l-methyLS-nitro-Z-imidazolecarboxylate, respectively, are obtained.

Use of methyl 1-methyl-5-nitro-2-imidazolecarboximidate in place ofethyl 1-methyl-5-nitro-2-imidazolecarboximidate in the above reactionsgives the corresponding thiosemicarbazone of methyl l-methyl-S-nitro-Z-imidazolecarboxylate. Similarly, use of1-(2-hydroxyethyl)-5-nitro-2-imidazolecarboximidic acid, delta-lactone,gives the thiosemicarbazone of 1-(2-hydroxyethylJ-5-nitro-Z-imidazolecarboxylic acid, delta-lactone.

EXAMPLE 16 Preparation of 2-(2-amino-l ,3,4-thiadiazol-5-yl)-l-methyl-S-nitroimidazole To a stirred mixture of ethyl1-methyl-5-nitro-2-imidazolecarboxylate thiosemicarbazone (0.050 g.,0.0018 mole) and ml. of absolute ethanol is added 0.3 ml. of 5.37 Nethanolic HCl. The mixture is heated at reflux for hours and is dilutedwith water. The solution is made alkaline with cone. ammonium hydroxideand the ethanol is evaporated. The yellow solid is filtered, washed withwater and dried, yielding 0.013 g. of the above compound.

In a similar manner, acid treatment of the mixture of 1 (1methyl-5-nitro-Z-imidazolecarboximidoyl)-3-thiosemicarbazide and ethyl1-methyl-5-nitro-2-irnidazolecarboxylate thiosemicarbazone, gives thetitle compound.

The same procedure used with methyl l-methyl-S-nitro-Z-imidazolecarboxylate thiosemicarbazone gives the above compound. Withethyl 1-methyl-5-nitro-2-imidazolecarboxylate,4-methyl-3-thiosemicarbazone and with ethyl1-methyl-5-nitro-2-imidazolecarboxylate, 4,4 dimethyl-3-thiosemicarbazone, there is obtained, respectively, 2-methylamino-5-(1-methyl-5-nitro 2 imidazolyl)-1,3,4- thiadiazole and2-dimethylamino-5 (1-methyl-5-nitro-2- imidazolyl)-1,3,4-thiadiazole.

EXAMPLE 17 Preparation of 2-(2-amino-l,3,4-thiadiazol-5-yl)-l-methyl-S-nitroimidazole 1-(1methyl-S-nitro-Z-imidazolecarboximidoyl-3-thiosemicarbazide is cyclizedas in Example 10 with the exception that the 0.3 g. of thethiosemicarbazide in 7 ml. of 6 N hydrochloric acid is replaced by 0.49g. of the thiosemicarbazide in 5 ml. of methanol plus 0.5 ml. ofconcentrated hydrochloric acid. The cyclization is also efiected by theuse of 0.49 g. of the thiosemicarbazide in 5 ml. of methanol plus 0.5ml. of 6 N ethanolic hydrogen chloride. In each of these variations, a78% yield of the title compound is realized. The cyclization is likewiseaccomplished by the use of dilute aqueous sulfuric acid, phosphoric,nitric, p-toluenesulfonic, benzene sulfonic, methylsulfonic orhydrobromic acid.

EXAMPLE l8 Utilization of compounds of the present invention incontrolling fowl typhoid The eflfectiveness of the compounds of theinvention or products prepared from the intermediate compounds thereindisclosed for controlling fowl typhoid is demonstrated by the followingtests.

One day old sex-linked pullet chicks are infected orally by gavage with0.5 ml. of a 10- dilution of a five-hour Trypticase Soy Broth culture ofSalmonella gallinarum, the causative agent of fowl typhoid. Each chickreceives approximately 6X 10 viable cells.

Medication is administered continuously in the feed, beginning 3 hoursbefore infection and continuing for 10 days, at which time the test isterminated and the number of survivors in each group recorded. Theresults are compared with two control groups of chicks, the first groupcomprising 20 chicks which are infected and untreated, and the secondgroup comprising 10 chicks which are infected and untreated. The resultsof the test are set forth in the following table:

1 Dose is in terms of percentage by weight of the feed.

EXAMPLE 19 Utilization of a compound of the present invention incontrolling enteritis This example demonstrates the effectiveness of2-(2- amino-1,3,4thiadiazol-5-yl)-l-methyl-S-nitroimidazole incontrolling enteritis. Three groups of ten female Swiss Webster miceweighing 20 gm. are infected intraperitoneally with 0.5 ml. of 10-dilution of a five-hour Trypticase soy broth culture of Salmonellacholemesuis var. kunzen- 13 dorf, the causative agent of enteritis inpigs, an organism originally recovered from a field outbreak ofSalmonella choleraesuis var. kunzena'orf in pigs. Each mouse receivesapproximately 4.6 X 10 cells as the inoculating dose.

The mice are fed a medicated feed, which is a commercial mouse chowcontaining the compound 2-(2- amino 1,3,4thiadiazol-S-yl)-1-methyl-5-nitroimidazole, for 3 hours before infectionuntil 7 days after infection. The mice are held for an additional 7 daysafter the medication is stopped, and the number of survivors in eachgroup recorded. The medicated feed is prepared by thoroughly admixingcalculated amounts of 2-(2-amino-1,3,4-thiadiazol--y1)-l-methyl-5-nitroimidazole with commercial mousechow to provide essentially uniform distribution in the feed offered.The above results are compared with two control groups of ten mice each,in which one control group is infected and untreated, and the secondcontrol group is uninfected and untreated. The results of the test areset forth in the following table:

1 Dose is in terms of percentage by weight of commercial mouse chow.

EXAMPLE 20 Utilization of compounds of the present invention incontrolling colibacillosis This example demonstrates the effectivenessof 2-(2- amino-1,3,4-thiadiazol-5-yl)-1-methyl-5-nitroimidazole incontrolling colibacillosis in poultry.

Three groups of 10 five-day old sex-linked pullet chicks are infectedparenterally, in the left thoracic air sac, with 0.2 ml. of a 10-dilution of a Trypticase soy broth culture of Escherichia 0011', thecausative agent of colibacillosis in poultry. The compound2-(2-amino-1,3,4-thiadiazol-S-yl)-1-methyl-5-nitroimidazole isadministered by gavage as a single oral dose in an aqueous solution orsuspension, and the chicks are permitted to feed ad libitum. Anutritionally balanced diet is employed. Twelve days after treatment,the test is terminated and the number of survivors in each grouprecorded. The results are compared with two control groups of chickseach, in which one control group is infected and untreated, and thesecond control group is uninfected and untreated. The results of thetest are set forth in the following table:

Uniniecteduntreated 20 20 Dose is in terms of milligrams per kilogram ofbody weight.

EXAMPLE 21 Control of T richomonas vaginalis infections The activity ofthe compounds of the present invention for controlling Trichomonasvaginalis infections is demonstrated in the following example whereinmice are inoculated with 50,000 culture-derived Trichomonas vaginalis(Thorns strain) and then treated with test compound to determine whethersuch compound is active for controllng the above named disease organism.In these tests 100, 200 or 1,000 mg./kg. of body weight of test compoundis administered in a single oral dose by gavage one day afterinoculation. Six days after inoculation, scrapings from the subcutaneoussites of inoculation are searched microscopically for motiletrichomonads and antitrichomonal activity is concluded in thoseinstances where motile trichomonads are eliminated from lesions presentat the site of inoculation.

In these tests all mice received a standard commercial mouse chow andwater provided ad libitum throughout the test period. The data obtainedare provided in table form below.

TABLE IV Total Percent- Dose, mice age Compound rug/kg. infected Clearedcleared Z-(SqnethyliH-l,2A-triazol-3- 200 5 5yl)-lmethyl-5-nitroimidazole- 2-(5-amino-4H-1,2,4-triazol3- yl)-1-methyl-finitroimidazole 1, 000 5 5 1001-(1-n1ethyl-5-nitro-2-imidazolecarboximidoyl)semicarbazide 100 5 2 40We claim: 1. A compound of the formula:

References Cited UNITED STATES PATENTS 2/1971 Asato et al. 260--309OTHER REFERENCES Merck, Chem. Abst., Vol. 63, columns 608-9 (1965).QDLAS 1.

Merck, Chem. Abst., Vol. 64, columns 2093-4 (1966). QD1.A51.

NATALIE TROUSSOF, Primary Examiner US. Cl. X.R.

260244 R, 306.8 D, 307 G, 308 R, 308 C; 424-248, 269, 270, 272, 273

